Well the first thing I noticed is that you've set the Turn Clock setting to 15 seconds, which is half the default value. So players are getting 8 seconds before seeing a 7 second warning, as opposed to the normal 20 seconds before seeing a 10 second warning. Are you on a VPS or a dedicated server? If it's a VPS, it could be that another account on that server spikes the CPU every once it while, causing some packet delay. Do you ever notice any lag in response? Anyway, I'd suggest conducting an experiment and change some of your tables to a 30 second Turn Clock and see if the number of auto folds goes down.